Like an old friend whose mere memory brings tears, “56 Up,” the latest film in the greatest cinematic experiment in sociology and psychology ever attempted, returns to theaters. Every seven years, a new installment in “Seven Up!”, an updated feature film boiled down from the British TV documentary series, reminds us of our mortality even as we see the years pass for the British subjects of these films.

The world met them in “Seven Up!”, fourteen British children representing what was then, a pretty broad sample of British society – poor East End tykes, orphans, a child of mixed race, a country boy, and the posh-accented scion of landed gentry and the professional classes.

Every seven years we see how Jackie and Lynn, Tony, Suzy, Symon, Neil and the others have changed – how the attitudes and personalities they expressed as talkative seven year-olds have manifested themselves in adult life.

It’s an exploration of that Jesuit saying, “Give me a child until he is seven and I will give you the man.” Are we really fully formed at seven?

We see working class Sue as a teen, declaring that she’d “like to have a full life” before getting married. But she married at 24, and was divorced by the time “35 Up” appeared.

Paul, bullied as a child, moved to Australia, married, raised a family, and lifelong lack of self-confidence aside, displays that British pluck – “People tend to get on with their lives, no matter what.”

Some cope with illness and loss. The famously lost Neil, homeless during some stretches of film series, is reminded that he dropped out of college, never married, but found purpose as a small town lay minister and elected official. “No formal education can prepare you for life,” he insists, adding that he’s not interested in living a long life – “Seventy or so, and that’ll be enough.”

But almost to a one, the others interviewed speak of an education being “the most important thing” you can leave your kids. It levels the British playing field, lessens the impact of class.

Some dropped out of appearing in the series, thanks to the notoriety, the raw exposure – the edited version – of their lives. But they came back. Many were more political than they are in their 50s, though most still complain about the darkness of Britain’s (Margaret) Thatcher years – the 1980s and worry they’re facing another dark age.

Tony wanted to be a jockey, had to settle for driving a taxi, married and made enough to buy a vacation villa in Spain, complete with pool.

The psychology of the piece comes from the candid nature of the questions, then and now. Kids, then adults, talk about their concept of love, happiness, success, their worries, fears and hopes. The sociology comes from the way Britain has changed over their lives – a vast influx of immigrants that prompt Tony, the taxi driver, to make intemperate remarks. “None of us got to decide THEY got to come.” Interviewer-director Michael Apted to wonder if he’s racist. But he lets Tony explain himself – the hardship of economic competition from that influx.

Apted, involved with the series from the start, went on to make “Coal Miner’s Daughter,” a Bond film, action pictures, a pretty solid career in the movies. But this is what he will be remembered for, prying, interrogating and charming these kids turned adults every seven years, patiently pulling together confessional interviews that paint wonderful portraits of people through the long course of their lives. He forces them, and us, to take stock every seven years. Not a bad idea.

Some have grown to question the purpose of the series (class warfare, a few upper class ones insist) and their place in it. But their skepticism is rather like the pessimism that pervaded some chunks of their lives – “35 Up” through, say, “49 Up.” This too, shall pass.

Despite fears for the British version of what we like to call “The American Dream” – -home ownership, financial security, a healthy, long life — “56 Up,” feels like the most hopeful film of them all — amusing, entertaining, and touching. Some are still enduring trials. But many have found their place, a contentment that feels so very British. They’ve kept calm. They’ve carried on.